Celtics rock TD Garden with gritty Game 7 win over the Wizards

Boston Celtics fans cheer as guard Isaiah Thomas runs up the court after a made basket during the fourth quarter of Game 7 of a second-round NBA playoff series against the Washington Wizards on Monday in Boston.AP

Boston Celtics guards Isaiah Thomas (4) and Marcus Smart (36) celebrate with center Kelly Olynyk (41) after Olynyk sank a basket during the fourth quarter of Game 7 of an NBA playoff series against the Washington Wizards on Monday in Boston.AP

Boston Celtics forward Jaylen Brown (7) dunks over Washington Wizards guard Bojan Bogdanovic during the fourth quarter of Game 7 of a second-round NBA playoff series on Monday in Boston. The Celtics won, 115-105.AP

The Celtics punched their ticket to the Eastern Conference Finals with Monday’s 115-105 Game 7 win over the Washington Wizards at TD Garden. That win and the looming showdown with the Cleveland LeBrons delivered the instant gratification. Tuesday’s Draft Lottery and the Celtics 25 percent chance to land the top pick will bring the long-range hope.

The gritty Game 7 win will let Celtics fans easily swallow whatever happens in the Lottery, which is nice, since luck has not been on Boston’s side with these things in the past. Even if the pick slips to No. 4 (the lowest possible outcome for the Celtics, which has the right to swap picks with Brooklyn), the giddiness from beating the Wizards and the anticipation of facing the Cavaliers will still goose bump the fan base.

Some might tell you winning Game 7 and getting out of the second round was icing on the cake for this season. They’ll tell you the trip to the Conference Finals puts the Celtics ahead of schedule, that the real timeline for the next Boston championship is driven by the progress and production of 20-year-old Jaylen Brown and whoever the Celtics land in the next two drafts.

There is some truth to that, but only some. Losing a Game 7 at home would have staggered the franchise. It would have diminished the regular season that brought the No. 1 seed in the East, it would have derailed the confidence this team has built, and it would have been extra painful coming against the disliked Wizards.

Consider this: Going into Monday night’s game there have been 127 Game 7’s in NBA Playoff history, and the home team was 101-26 in those games.

So there was more at stake than just extra icing on Monday. And the Celtics claimed the winner-take-all pot the same way they earned the No. 1 seed in the East - depth, grit and shotmaking.

All year long Boston has relied on its bench, but the depth disappointed in Game 6 in Washington. The Celtics reserves scored just five points in that one, the lowest bench total for any team in any game in this year’s playoffs.

But the bench production made an early return on Monday. Brown made a surprise first-quarter appearance and put up five points and two boards in the opening frame. And when Amir Johnson picked up two fouls in the first six minutes of the first, Kelly Olynyk came in and contributed five points, an assist and a rebound in the opening quarter … but his best work was yet to come.

Olynyk has been criticized as dirty and mocked as a doofus. In some ways, he was the poster child for the Celtics, a team that many called the worst No. 1 seed in NBA history. But that worst No. 1 seed is now preparing to host Game 1 of the Conference Finals, thanks in large part to the 26 points, five rebounds and four assists from the doofus Olynyk.

Brown finished with nine points and Marcus Smart (more on him later) added 13 as the Boston reserves outscored their Washington counterparts, 48-5.

“I think the bench was a big factor in Game 5 and Game 7, and it certainly was as well throughout the series. The home team’s bench seemed to play really well,” Boston Coach Brad Stevens said. “So I thought our guys did a great job. Obviously Kelly gave us that enormous lift.

Despite Boston’s bench contributions, Washington held a 55-53 halftime lead. The Wizards then attacked Isaiah Thomas relentlessly to start the third, exposing the defensive liabilities of Boston’s offensive star. The result was a 70-64 Washington lead midway through the third.

That’s when the grit kicked in. Yes, it probably got a boost from the depth, which helps the Celtics stay fresher than most teams in the second half, but Boston’s late-game push on Monday was more about their will power and mental toughness than it was about Washington’s fatigue.

Powered by physical defense and eight points from Thomas (29 points, 12 assists), the Celtics went on a 13-3 run to close the third and take an 85-79 lead into the final quarter.

“Going down six in the third, I thought we stayed the course,” Stevens said. “We made the next right play and turned our level up a little bit. I thought at the start of the third we were getting outplayed, (but) from five minutes on we were pretty good.”

The Celtics pushed their lead to 13, 94-81, on a Thomas 3 with 10:00 left in the fourth, but the Wizards still weren’t done. They rode the hot shooting of Bradley Beal (38 points), quieted the insane Garden crowd and trimmed the lead to 94-88 with 8:49 to play, forcing Stevens to use a timeout.

Like he has during all of his four seasons in Boston, Stevens drew up a pretty play out of that timeout that led to a layup for Olynyk. The coach has become legendary for those plays, and they have become a staple for the Celtics offense. But the out-of-bounds plays don’t really mean much unless Boston is doing what it really needs to do on offense - hitting shots.

In the end, it’s really a simple game. Make shots and you win. Miss and you don’t. The Celtics shot 53.2 percent on Monday and were 4-0 in this series when they shot more than 50 percent. In their three losses, they shot less than 45 percent.

Smart wrapped up the three keys - depth, grit and shotmaking - in the play that effectively iced the game. The linebackerish guard who comes off the bench bullied his way to the rim with :38.3 seconds left and finished a tough layup to make it 114-105 and finally put Washington’s season to rest.

While the Wizards consider funereal arrangements, the Celtics can bask in their bright future on Tuesday and then revel in the delight of right now against Cleveland on Tuesday. It’s a good time to be a Celtics fan, no matter which world you like.